In the hospital, surgical instruments and also other medical equipment are customarily cleaned by machine by using alkaline cleaning compositions, and then disinfected chemically or thermally. Such strongly alkaline compositions may act aggressively toward sensitive surfaces. Immediately after they have been used, surgical instruments with contamination from blood are frequently placed, for example, into a disinfecting solution, where they initially remain until cleared out into the washing machine for cleaning. The disinfectant causes the blood to coagulate, and the active disinfecting ingredient causes denaturing of the protein constituents present in the blood. Particularly persistent blood residues of this kind are frequently removable only by means of alkaline active chlorine-containing cleaning compositions. The oxidizing active chlorine component brings about the decomposition of the denatured protein constituents. Other constituents of disinfectants as well, such as iodine, for example, may form residues that are difficult to remove.
The alkaline active chlorine-containing cleaners have the disadvantages that they comprise hazardous substances liable to declaration, that their handling necessitates special precautionary measures in order to protect the operating personnel, and that they constitute an unwanted environmental pollution in the wastewater.
U.S. Pat. No. 4,243,546, EP-A-0 481 663, and EP-A-0 730 024 disclose enzyme-containing cleaning compositions which are able to bring about enzymatic degradation of blood proteins in particular.
EP-A-1 021 519 discloses an enzyme-free cleaning composition concentrate for cleaning surgical instruments. A disadvantage stated for the enzymatic cleaners therein is that the enzyme activity may subside in the course of prolonged storage.
EP-A-1 327 674 discloses a cleaning composition concentrate for medical instruments that comprises an alkanolamine, enzymes, and aminopolycarboxylic acids as complexing agents.